The present invention relates to computer technologies. In particular, the present invention relates to computer gate control circuitry and apparatus.
Today a typical personal computer like an IBM PC/AT comprises three major devices: an input unit, a central processing unit (CPU) and an output unit. An input unit is often a keyboard, an output unit is often a monitor, where both are connected to the CPU as shown in FIG. 1. Inside the CPU, referring to FIG. 2, there are several major parts: a main board, a power supply, a floppy disk drive, a hard disk drive, where all are mounted on a case frame, a floppy and hard disk drive controller card vertically inserted onto one of the input/output (I/O) slots on the main board and also mounted on the case frame, and a video card inserted onto another I/O slots and mounted on the case frame. The power supply is connected to the main board and the disk drives through power cables. The controller is connected to the disk drives through controller cables. The keyboard is connected to the main board through a keyboard cable, and the monitor is connected to the video board through a monitor cable.
The floppy and hard disk controller card is inserted onto one of the I/O slots on the main board, so it is one kind of the so called I/O cards. Other examples of I/O cards are the video card which is used for the monitor, & serial port card which is often used for a mouse (a pointing device) or a modem (a communication device), parallel port card which is often used for a printer or a plotter, and so on. A computer has a certain I/O address map to send signals to different I/O cards, and these addresses are usually represented in hexadecimal (HEX) codes. For example, in an IBM PC/AT personal computer the I/O address (in HEX code) for the floppy disk drive controller is 3F8-3FF, for the hard disk drive controller is 1F0-1F8, for the monochrome video card is 3B0-3BF and for the color video card is 3DO-3DF. Usually two identical I/O cards with identical I/O addresses can not be used together on one computer because they may conflict with each other.
In the computer manufacture and service industry there is often a need to use a single computer to control a multiplicity of hard disk drives for efficient and effective operations such as preparation, diagnosis or data storage. The controller on today's market for a personal computer usually can only control up to two hard disk drives where one of them is set as drive 1 and the other drive 2. It is also built with two I/O addresses: a primary address and a secondary address. Sometimes two identical controllers can be put into one computer so it can control up to four identical hard disk drives with two of them as number 1 and the other two as number 2. However in order to do so one of the controllers has to be set at the primary address and the other the secondary. But on some controllers, the secondary address is not always available. Thus there is still only one controller that can be always used in one computer and there are still only two hard disk drives that can be always controlled by one computer.
Furthermore, out of these two hard disk drives usually only one can be the hard disk drive to be operated for preparation, diagnosis or data storage as a "target drive". Also when a second hard disk drive is connected to the same controller, it has to be physically set via a jumper as drive 2, and after the preparation set back as drive 1. The reason is that the above operations are often performed by executing the software programs loaded on a hard disk drive so one of the two hard disk drives controlled by a controller has to be used to serve as a "source drive" for that purpose and must not be disturbed. Alternatively a floppy disk drive can be used as the "source drive" but it creates slow and cumbersome operation where a few floppy diskettes have to be used to preparing the "target" hard disk drive. Therefore when a single computer with a source drive is used, there is only one more "target drive" that can be added. So using a single computer for operations such as preparation, diagnosis or data storage on hard disk drives is so far still a one-on-one operation.
One suggestion of using a single computer to control a multiplicity of hard disk drives is to build a special computer which can assign multiple different addresses to a multiplicity of identical controllers, and each of these identical controllers is built with a circuit which can decode the different addresses. But the cost of building such type of computers and controllers does not justify the benefit and the off the shelf computers and controllers can not be used.
It will be beneficial if there is a gate control circuitry and apparatus which can be used, together with a single computer, so the computer can simultaneously and selectively send signals to a multiplicity of identical controllers and through them control a multiplicity of identical hard disk drives.